import subprocess
import os
import numpy as np
import soundfile as sf
from typing import Optional
from ..config import settings


def mix_audio(
    video_path: str,
    segments: list[dict],
    output_path: str,
):
    temp_dir = settings.temp_dir

    original_audio_path = os.path.join(temp_dir, "original_audio.wav")
    _extract_audio(video_path, original_audio_path)

    original_audio, orig_sr = sf.read(original_audio_path)
    if len(original_audio.shape) > 1:
        original_audio = original_audio.mean(axis=1)

    target_sr = 24000
    if orig_sr != target_sr:
        import librosa

        original_audio = librosa.resample(
            original_audio, orig_sr=orig_sr, target_sr=target_sr
        )

    total_samples = len(original_audio)
    danish_track = np.zeros(total_samples, dtype=np.float32)

    for seg in segments:
        danish_audio = seg.get("danish_audio")
        if danish_audio is None or len(danish_audio) == 0:
            continue

        start_sample = int(seg["start_time"] * target_sr)
        end_sample = min(start_sample + len(danish_audio), total_samples)
        actual_len = end_sample - start_sample
        danish_track[start_sample:end_sample] += danish_audio[:actual_len]

    volume_envelope = np.ones(total_samples, dtype=np.float32)
    for seg in segments:
        start_sample = int(seg["start_time"] * target_sr)
        end_sample = int(seg["end_time"] * target_sr)
        volume_envelope[start_sample:end_sample] = 0.23

    orig_adjusted = original_audio * volume_envelope

    mixed = orig_adjusted + danish_track
    peak = np.max(np.abs(mixed))
    if peak > 0.99:
        mixed = mixed / peak * 0.95

    mixed_path = os.path.join(temp_dir, "mixed_audio.wav")
    sf.write(mixed_path, mixed, target_sr)

    _replace_audio(video_path, mixed_path, output_path)

    for f in [original_audio_path, mixed_path]:
        if os.path.exists(f):
            os.remove(f)


def _extract_audio(video_path: str, output_path: str):
    cmd = [
        "ffmpeg",
        "-y",
        "-i",
        video_path,
        "-vn",
        "-acodec",
        "pcm_s16le",
        "-ar",
        "24000",
        "-ac",
        "1",
        output_path,
    ]
    result = subprocess.run(cmd, capture_output=True, text=True)
    if result.returncode != 0:
        raise RuntimeError(f"Audio extraction failed: {result.stderr}")


def _replace_audio(video_path: str, audio_path: str, output_path: str):
    cmd = [
        "ffmpeg",
        "-y",
        "-i",
        video_path,
        "-i",
        audio_path,
        "-c:v",
        "copy",
        "-c:a",
        "aac",
        "-b:a",
        "192k",
        "-map",
        "0:v:0",
        "-map",
        "1:a:0",
        "-shortest",
        output_path,
    ]
    result = subprocess.run(cmd, capture_output=True, text=True)
    if result.returncode != 0:
        raise RuntimeError(f"Audio replacement failed: {result.stderr}")